HydroxyMethylFurfuraldehydeor 5-hydroxymethyl-2-furfuraldehyde or sometimes just HydroxyMethylFurfural (HMF) In Honey

HydroxyMethylFurfural is an aldehyde, whose molecule is illustrated at right,
which can be used as an indicator of honey quality limits are set by food standard
agencies and in the EC, UK and Japan these figures are listed in the table below.

Legislative Source

Maximum Moisture Level

Maximum HMF Level

Minimum Levelof Reducing Sugar

MinimumDiastase Activity

EC Directive 1974 (74/409/EEC)

21% (18%)

40mg/kg (under 20mg/kg)

65%

8 (Schade scale)

UK Honey Regulations 1976

21% (18%)

80mg/kg (under 20mg/kg)

65%

8 (Schade scale)

Japan (Fair Trade Authority)

21% (18%)

5mg/kg (under 1mg/kg)

65% (70%-80%)

Figures in brackets are the levels recommended by traders for honey arriving at on
importation in order that the processed product complies with the legislation.
The UK has a special derogation from EC law allowing it to import honey at 80mg/kg HMF.
All other EC countries have to abide by the 40mg/kg limit.
The USA does not have specific honey legislation and sets no legal limits for HMF or
diastase activity. Quality being guaranteed by importers.

HMF is actally produced as a result of the breakdown of fructose in the
presence of an acid, the reaction is temperature sensitive so that a small amount
of deterioration takes place in the honey even at room temperatures and the reaction
is very much speeded up at elevated temperatures.

High levels of HMF (greater than 100 mg/kg) can be an indicator of possible
adulteration of the product with inverted sugars or syrups.

Low levels of HMF are quite natural and will increase with age or heat
treatment of the honey.

Levels of HMF higher that 10%in extracted honey may indicate excessive
heating during the extraction process.

Bulk Honey that is traded by export is usually required to be below
10 mg/kg to enable further processing and be assured of reasonable shelf life
before the level of 40 mg/kg is reached.

Honey that is produced in hot climates can often be over 100 mg/kg, owing
to high temperatures occurring during processing, (the bees will keep the temperature
down while the honey is still in the hive).

Time and temperature both have an effect... Honey held at an ambient temperature
of 30°C for 6 months will accumulate as much or more HMF than a similar sample
of honey quickly heated to 70°C for 5 minutes and then cooled.

Measuring HMF

The Winkler method although still popular in Germany (it's country of origin)
this photometric method is considered to be out of date.

The most commonly used method today is direct measurement using HMF's
spectral absorbance at 284nm.

D.A.C.

"HMF pdf" on the top left is an article written by Brian P. Dennis. R.P.